Emerson Exchange 365

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Operability of Device Control Function Block

Hello DeltaV Community,

I'd like to use Motor 21 with Force SP, Interlocks & Permissives V5.2 PCSD Device Control module to configure an interlock and a permissive to trip and unlatch the trip in a motor protection relay. However, I do NOT want to give operator the ability to start/stop the motor from the DCS -- these controls are achieved via a local control panel. I haven't found the DC block's "operability" feature, nor its mention in BOL. Is this option available in DeltaV ver. 11. 3.1?

dmitriy sagadiev

• 4 May 2020 3:38 PM
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5 Replies

• Matt Stoner

  

  • 4 May 2020 3:48 PM

  You can accomplish by setting the DC1/TRK_IN_D to True and the block will follow what the PV is doing when being controlled from the field. You can also enable only the CAS mode on the DC block and change the Default Target to CAS as well so the operator interface will indicate there is nothing he/she can do from the Faceplate.

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• Hassan.hameed

  

  • 4 May 2020 7:02 PM

  In reply to Matt Stoner:

  You can use the ACT block write expression this expression can write on SP as your Pump philosophy status

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• Matt Stoner

  

  • 4 May 2020 7:22 PM

  In reply to Hassan.hameed:

  No need for an ACT block to write the SP_D (only when in AUTO, CAS_IN_D when CAS) to add more loading to the system when defaulting DC1/TRK_IN_D does the functionality without any additional load. This also gives an indication with MODE.ACTUAL being LO as well.

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• dmitriy sagadiev

  

  • 4 May 2020 8:36 PM

  In reply to Matt Stoner:

  Thank you Matt. Presently, the module has Track_Logic CALC block connected to the TRACK_IN_D. Do I need to convert and leave the module classless, remove the CALC block and its connection, and set DC1 TRACK_IN_D to True?

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• Matt Stoner

  

  • 4 May 2020 8:44 PM

  In reply to dmitriy sagadiev:

  You must have a different PCSD class than a normal Motor 21, depending on what is there and if you need it or not. I would think not and just removing all that and set the default TRUE and make the default status GoodNonCascade. Don't change the class in case others are using. Create a new class or break the instance from class based and make your changes.

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